Generally, vehicles, especially automobiles, are equipped with a wide variety of lights serving many different purposes. These purposes include dashboard lighting, interior overhead lighting, exterior lighting, trunk lighting and under-hood lighting, to name only a few. An even wider variety of lighting needs are presented by boats, air planes and other vehicles. Typical light assemblies include a housing with a lens and an opening in the housing for access to a lamp inside the housing.
In many applications, an adjustable reflector is mounted within the housing. With this type of lamp assembly, the housing is mounted securely to the vehicle, and the reflector position is adjusted within the housing to modify the direction of the beam of light emitted by the light assembly. Access to the rear portion of the reflector is provided by an opening in the housing. This allows for replacement of the lamp which is mounted to the reflector. Accordingly, the opening in the housing is substantially aligned with the rear of the reflector for easy access to the lamp.
The above described arrangement, while very useful in allowing for replacement of the lamp, increases the susceptibility of the light assembly to degraded performance due to the introduction of water, dirt or other debris into the lamp assembly. Accordingly, it is known to provide a sealing member between the light assembly housing and the reflector. Because the reflector is moveable, any such sealing member must be capable of allowing relative motion between the housing and the boot. One approach to providing a sealing member is to use flexible material. One such material is Ethylene Propylene Diene Monomer (EPDM) rubber.
EPDM possesses a number of desired characteristics. EPDM is capable of withstanding wide temperature variations without cracking or deteriorating. EPDM also offers high tensile strength, extreme elongation capabilities to several times its original size, and is generally compatible with other materials used in light assemblies. In a typical light assembly using EPDM, the rubber is mechanically or chemically sealed to the light housing in order to provide a hermetic seal.
The need for mechanical or chemical sealing in the light assembly process disadvantageously results in additional manufacturing steps and material. Every step in the assembly process adds time, complexity and expense to the manufacturing process. Thus, a reduction in the number of steps needed to accomplish assembly has a direct impact on lowering the manufacturing time and costs of the light assemblies. Furthermore, there are additional costs associated with stocking the increased number of parts or materials used in mechanically or chemically sealing EPDM. Thus, a reduction in the parts or material used to seal the light assemblies has a direct impact on lowering the manufacturing time and costs of the light assemblies.
Similarly, the manufacturing cost of the light assemblies has a direct impact on the overall cost of a vehicle. Thus, as the process of manufacturing the light assemblies is simplified, the cost of manufacturing can be reduced as increased manufacturing efficiency is realized.
Throughout the above processes, quality is an important consideration. The seal between the reflectors and the light assembly housings must be sufficiently robust that the performance of the light assemblies is not degraded by mishandling during manufacture, shipment and vehicle assembly processes. Furthermore, depending on the application, light assemblies must function reliably under severe operational conditions such as severe shock and vibration, a wide range of temperature, and exposure to water, oil and dirt.
It is desirable, therefore, to provide a hermetically sealed light assembly that does not require additional parts or materials. It is further desired that the light assembly be of simple and reliable construction. Moreover, it is desired that the light assembly not be of increased cost as compared to known light assemblies in the prior art while providing a reliable seal.